The Or Immediate instruction performs a logical bit by bit “or” between a byte in memory and an immediate constant. Operand 1, the target, is a byte in memory and Operand 2, the source, specifies the immediate constant. The byte in memory is or-ed internally with the immediate constant and contains the final result. The immediate constant is not changed. The table below shows the results of “or-ing” two bits together.

Bit 1 Bit 2 Result

0 0 0

0 1 1

1 0 1

1 1 1

This instruction sets the condition code as follows:

0 if all target bits are set to 0. Test this condition with BZ or BNZ.

1 if any target bit is set to 1. Test this condition with BM or BNM.

Some Unrelated Or Immediates

BYTE1 DC X’00’

BYTE2 DC X’FF’

BYTE3 DC X’C3’

OI BYTE1,X’12’ BYTE1 = X’12’ Condition Code = 1

OI BYTE1,X’FF’ BYTE1 = X’FF’ Condition Code = 1

OI BYTE1,C’A’ BYTE1 = X’C1’ Condition Code = 1

OI BYTE1,B’11110000’ BYTE1 = X’F0’ Condition Code = 1

OI BYTE1,B’00000000’ BYTE1 = X’00’ Condition Code = 0

OI BYTE2,X’12’ BYTE2 = X’FF’ Condition Code = 1

OI BYTE2,X’FF’ BYTE2 = X’FF’ Condition Code = 1

OI BYTE2,C’A’ BYTE2 = X’FF’ Condition Code = 1

OI BYTE2,B’11110000’ BYTE2 = X’FF’ Condition Code = 1

OI BYTE3,X’12’ BYTE3 = X’D3’ Condition Code = 1

OI BYTE3,X’FF’ BYTE3 = X’FF’ Condition Code = 1

OI BYTE3,C’A’ BYTE3 = X’C3’ Condition Code = 1

OI BYTE3,B’11110000’ BYTE3 = X’F3’ Condition Code = 1